Ingot mold and ingot



April 29, 1941. E. GATHMANN INGOT MOLD AND INGOT 2 Sheets-Sheet 1 FiledJan. 2'7, 1941 Emil Ciafhmann 62%; vw fi Ap il 29, 1941- E. GATHMANN2,240,396

INGO'I MOLD AND INGOT Filed Jan. 27, 1941 2 Sheets-Sheet 2 WW I 2' EmilGafhmann r flww'n dy f AW,

Patented Apr. 29, 1941 INGOT MOLD AND INGOT Emil Gathmann, Baltimore,Md., assignor t0 Gathmann Research Incorporated, Catonsville, Baltimore,Md., a corporation of Maryland Application January 27, 1941, Serial No.376,221

8 Claims.

This invention relates to ingot molds and ingots, and more particularlyto improvements in cross sectional contours of ingot mold chambersandingots.

It is now well known to those skilled in the art that the metal ofingots of generally rectangular cross section may be more effectivelyworked during initial roll passes if the mid-portions of their sides areprovided with projecting salient portions'which are adapted to besWedged outwardly, and to a large extent parallel with the axes of therolls, rather than flowed longitudinally as happens in ingots ofrectangular cross section the sides of which are not provided with suchprojecting salients. An ingot having a contour including such outwardlyprojecting surfaces at the edges of relatively narrow primary sideportions is disclosed and claimed in my United States Patent 1,745,089of January 8, 1930. The ingot described in this patent includes medialprimary side portions each comprising two outwardly extending initiallyroll contacting convex salients connected by a single inwardly belliedor curved primary side portion. In my United States Patent 1,767,174 ofJune 24, 1930, there is described and claimed an ingot including primaryor initially roll contacting side portions comprising a plurality ofalternate smoothly curved inwardly bellied and outwardly belliedcorrugations.

These known contours have provided advantages in the solidification androlling of ingots but some difficulty has been experienced with ingotshaving prior art contours because of the formation of cracks, usuallysubcutaneous cracks,

connected along its opposite side edges respectively with relativelysmoothly curved concave portions which, at any cross section of theingot,

are defined by arcs having substantially a common center lyingsubstantially on the neutral line of peripheral shrinkage generallynormal to the primary side portion. Thus, the two smoothly curvedconcave portions of each primary side respectively form spaced .segmentsof the same circle, the relatively abruptly curved convex portionintervening between the two segments.

The numerous and complex factors influencing the behavior of steel insolidifying and cooling, and in being reduced by rolling processes, arenot all understood entirely and the beneficial effects upon the finalrolled product produced by employing contours of the character referredto therefore cannot be explained categorically. The improved resultspossibly are due to the particular formation of ingot metal crystalsinduced by the chilling mold walls having contours complementary to theingot surface contour described above which apparently strengthens theingot locally at the zone in which cracks heretofore have beentroublesome; but it is possible that the novel ingot contour causes theapplication of sub-cutaneous rolling pressure in such a direction ordirections as to avoid tearing or pulling apart of the metal, 7

Another object of the invention is to provide an ingot and mold forproducing the same which have contours characterized as explained above.More specific objects will become apparent from a reading of thefollowing detailed description, the appended! claims, and theaccompanying drawings, in which:

Figure 1 is a central vertical sectional view of an ingot mold embodyingthe invention;

Figure 2 is a horizontal half section taken on the line 2-2 of Figure 1;

Figure 3 is a somewhat diagrammatic partial horizontal section taken onthe line 2-2 of Figure 1 and drawn on an enlarged scale;

Figure 4 is a perspective view of an ingot embodying the invention andhaving the contour complementary to the mold contour disclosed inFigures 1, 2 and 3;

Figure 5 is a horizontal sectional view'of the ingot shown in Figure 4and drawn on a slightly enlarged scale;

Figure 6 is a horizontal sectional view of another form of ingotembodying the invention; and

Figure 7 is a fragmentary horizontal and somewhat diagrammatic crosssectional view of an ingot mold having a contour complementary to thecontour of the ingot shown in Figure 6.

The invention may be embodied in various classes of molds and ingots.Generally stated, most commercial ingots are cast in verticallyextending molds which taper outwardly from bottom to top (big-end-upmolds) or taper outwardly from top to bottom (big-end-down molds). Thelargest tonnage of high grade or quality steel is produced in big-end-upmolds and the invention is illustrated as being embodied in a big-endupmold and ingot. However, it will be apparent from the followingdescription that the invention may also be embodied in molds and ingotsdiffering as to those characteristics of contour at the upper and lowerextremities thereof for facilitating the handling of the mold whensetting up a jag of molds and when removing ingots from the molds. Theinwardly tapering side and corner walls of the mold chamber merge attheir bottoms with a vconcavo-convex neckedin bottom portion B which mayhave a contour in vertical section somewhat similar to that disclosed inmy Patent 2,047,098 of July 7, 1936. The mold bottom wall is formed withthe usual bottom opening 0 which receives a sealing or stripping plug P.

As is well known, ingots which are cast on end or in vertical positionmay be similar or symmetrical as to all four sides or they may be in theform of slabs in which the two wider sides correspond with each other inoutline and the narrower sides are different from the wider sides butcorrespond with each other. The mold shown in Figures 1 to 3, inclusive,has an ingot forming chamber or matrix of generally rectangular crosssection the center lines of which are inidcated at T -T and T -T Themold chamber is defined by four concave corner-walls I defined by arcshaving radii R whose centers are at C All four side walls of the moldchamber are of the same contour so that a detailed description of oneside wall and its connection with the adjacent corner walls will besufiicient. Generally stated, the side walls comprise all of the wallsurface intervening between the concave corners I. Each of the sidewalls so considered is formed of a plurality. of sections or portionshaving relative dispositions, curvatures, and extents which have beenfound in tests and in commercial production to eliminate the subnormalto the side wall considered as a whole.

The opposite edges of the concave wall portion 2 merge with abruptlyconvex wall portions 3-3 defined by arcs whose radii R -R respectivelyhave their centers C -C lying outwardly 'beyond the side wall and beingdisposed relatively on opposite sides of the transverse center line T -TThe relatively abruptly curved convex wall portions 3-3 mergerespectively with relatively smoothly curved convex wall portions didefined by arcs whose radii IV -R have substantially a common center Clying substantially on the transverse center line T -T The wall portionsdl merge respectively with outwardly projecting primary side wallmarginal portions 5-5. In the mold shown in Figures 1., 2 and 3 theoutwardly projecting marginal wall portions 5-5 are curved concavely andare defined by arcs whose radii R -R have their centers at C -C withinthe mold chamber. The curvature of the outwardly projecting marginalwall portions 5-5 is not per so an essential feature of the presentinvention, the provision of curved wall portions at this point dependingupon the size of the mold. The contour shown in Figures 1, 2 and 3 isone which has been found to produce improved results in the use of amold the maximum cross sectional dimension of which is approximatelyfifteen inches. As will beexplained with reference to Figures 6 and 7,it may be desirable, when using larger molds, to provide fiat marginalportions at the edges of the primary side walls. The marginal portions5-5 are flanked, respectively, by secondary corner walls 6-6 which inturn merge with the adjacent corner walls I-l and which, in extendingfrom the wall portions 5-5 to the corners l-i, slant or incline towardthe transverse center line T -T the arrangement being such that theprimary side wall constituted by the concave portion 2, the convexportions 3-3, the convex portions 4-4, and the marginal portions 5-5 isdisposed outwardly away from the center line T -T more than thesecondary corner walls 6-6 and the primary corners I-l. Thus, an ingotcast in the mold will have a side surface contour such that the metal atand under the primary side surface corresponding to the mold primaryside wall portion constituted as set forth above will be subjected tothe initial rolling pressure.

' An important feature of the present invention is the provision of therelatively smoothly curved convex mold wall portions 4-4 which arestruck from the common center C on or substantially on the transversecenter line T -T and which both form segments of the periphery of thesame circle. Thus, as indicated by the dotted arcuate line IV in Figure3, each smoothly curved convex wall portion 4 is a. continuation of theother wall portion 4. In accordance with another feature of theinvention the radius R of each relatively smoothly curved convex wallportion 4 is substantially greater than the radius R of the relativelyabruptly curved concave wall portion 2 and also is substantially greaterthan the radii R of the relatively abruptly curved convex wall portions3. The ratio of the radius BA to the radius R and to each of the radii Rshould not be less than four to one and it should be greater than fourto one in most cases, particularly in the larger mold sizes. The moldshown in Figures 1 to 3, inclusive, has a maximum width of approximatelyfifteen inches and the radius R is about eleven times as long as theradius R and about eleven times as long as each of the radii R -R Thisconstruction provides a relatively deep salient on the neutral line ofshrinkage of the ingot cast in the mold and provides a very gradualslope to the marginal portions of the primary side surface of the ingot.The abrupt change of direction provided by the acutely curved convexportions 3-3 and concave portion 2 provides a correspondingly abruptoutwardly extending salient on the ingot lying on the neutral line ofshrinkage.

Preferably the root or bottom of the depression formed by the concavemold wall part 2 is disposed a little inwardly of the outermost portionsof the marginal walls (i-ii. An ingot cast in a mold so formed andhaving a corresponding or complementary contour will not cause dimcultysometimes encountered when as many as three outwardly extending ingotsalients are designed for initial contact with the rolls. Inconventional ingots having a multiplicity of outwardly extendingsalients intended to be aligned, the projection of a central salientoutwardly a little more than is intended results in rocking or cantingof the ingot in the rolls and consequent diamond-shaping in reduction.The arrangement of the concave wall portion 2 inwardly of the marginalwall portions as described above obviates such difllculties in rollingas is described in more detail in my Patent 1,810,041 of June 16, 1931..

The mold shown by way of example is substantially rectangular in crosssection, having its four primary side portions arranged in two pairswith the primary side portions of each pair being disposed opposite eachother.

An ingot produced in a mold such as disclosed in Figures 1, 2 and 3 willhave a contour generally complementary to or corresponding with the moldwall contour described above. Such an ingot I is shown in Figures 4 and5 and the various ingot surface portions are designated by the samenumerals as those which designate corresponding wall portions of themold with the exception that the numerals designating the ingot surfaceportions are primed. Thus, each of the primary ingot sides includes anoutwardly projecting relatively abruptly curved convex central portion2, the opposite longitudinal edges of which merge with relativelyabruptly curved concave portions 3-3, which in turn merge withrelatively smoothly curved concave portions 4'-4' which are flanked byoutwardly projecting convex marginal portions 5-5'. The outwardlyprojecting portion 5' at each marginal edge of the primary side surfaceis connected to the adjacent primary corner I by an inwardly slanting orinclined concave secondary corner portion 6.

The radius of the smoothly curved convex portions 4'-47 is located on orsubstantially on the neutral line of peripheral shrinkage N N normal tothe side surface as a whole and is substantially longer than the radiiof the abruptly curved concave portions 3-3, which latter radii havetheir centers on opposite sides of the neutral line of shrinkage N N andalso is substantially longer than the radius of the abruptly,

curved convex central portion 2', which has its center on the line ofperipheral shrinkage N --N within the ingot. These various radii are notindicated in Figures 4 and 5, but theyhave the same relation to eachother as the radii of the corresponding wall portions of the mold asshown in detail in Figure 3. The other neutral line of shrinkage isindicated at N N It will be observed that the relatively smoothly curvedconcave side surface portions 4-4' of the ingot form segments of thesame circle as is indicated by the ure 5.

Figure 7 shows a horizontal half section of a mold m with center lines t-t and t and dotted connecting line IV' in'Fighaving a contour moreespecially suited to molds larger than the mold illustrated in Figures:1, 2, and 3. The contour of the mold shown in Figure 'Iis suchas hasbeen found to produce good results for molds having a maximum crosssectional dimension of approximately nineteen inches. The marginalprimary sidewall portions I05-I05 are flat but otherwise the arrangementof concave and convex portions and the relative lengths of the radii ofsuch portions is generally similar to that of the mold shown in Figures1,

2 and 3. Thus, the mold. shown in Figure 7 includes a relativelyabruptly curved concave central wall portion I02 whose opposite edgesmerge with relativelyabruptly curved convex wall portions I03I03 whichin turn merge respectively with relatively smoothly curved convex wallportions I04-I04 connected at their outer ends to the flat marginalportions I05I05. Each marginal portion I05 is joined to the adjacentprimary corner wall MI by an inwardly slanting or inclined convexsecondary corner wall I06. The radius of the relatively smoothly curvedconvex wall portions I04 is about twenty-six times as long as the radiiof the abruptlyjcurved convex portions I03-I03 and about twenty-sixtimes as long as the abruptly curved concave portion I02. The centers ofthe arcs defining the several curved portions I02, I03 and I04 arelocated similarly to the centers of corresponding wall portions of themold shown in Figures 1, 2 and 3. The drawings do not include a verticalsectional view of the mold shown in Figure 7, but this mold may have anysuitable vertical sectional contour such, for example, as that shown inFigure 1.

Figure 6 shows an ingot i such as would be cast in the mold shown inFigure 7 and which, therefore, would have a contour complementary to orcorresponding with that shown in Figure 7. The neutral lines ofshrinkage are indicated at n -n and n n Each ingot primary side surfaceincludes an abruptly curved convex central portion I02 flanked byabruptly curved concave portions I03'I03 which merge, respectively, withrelatively smoothly curved concave portions l04'-l04 jointed at theirouter extremities to the fiat marginal portions I05I 05'. Each marginalportion I05 is connected to the adjacent primary corner IOI' by aninwardly slanting concave secondary corner portion I06. The relativelengths of the radii of the curved portions 7 of the mold wall portionsand ingot surface por-,

tions are substantially the same at all cross sections of the mold andingot main bodies, the only 1 substantial variation in' these relationsbeing in the short necked-in bottoms oihthe mold chamfl I bers andingots. e I

The mold and ingots disclosed her'ein 'have contours or are formed withcontours embodying theinvention and have bensucces'sful in theelimination of a very large part of the difficulty previouslyencountered when using prior art molds and ingots having generallyrectangular cross sections and comprising various types 'of fluted orcorrugated primary sides. As to the two sizes of molds and ingotsdisclosed by way of example, the relative dispositions, curvatures andextents ofthe primary mold wall portions and primary ingotsurfacelportions are nowpreferred. It will be understood, however,that'some changes may be made in the'contours disclosed herein withoutdeparting .from the invention as defined in the claims.

I claim: a 1. A metallic ingot having two oppositely disposed primaryside portions each of which comprises longitudinally extending outwardlyprojecting marginal portions, a longitudinally extending relativelyabruptly curved convex central. portion which, at any cross section ofthe ingot, is definedby an are having its center substantially on theneutral line of shrinkage generally normal to said primary side portion,two relatively smoothly curved concave portions respectively connectedto said marginali portions and-extending toward said central portion,and two relatively abruptly curved concave portions respectivelyinterposed between andconnecting the opposite longitudinal edgesof saidcentral portion with said relatively smoothly curved concave portions,said relatively smoothly curved concave portions, at any cross sectionof the ingot, being defined by arcs having substantially a common centerlying substantially on said neutral line of shrinkage, and saidrelatively abruptly curved concave portions at any cross section of theingot, being defined by arcs having their respective centers on oppositesides of said neutral line of shrinkage.

2. A metallic ingot having two oppositely disposed primary side portionseach of which comprises longitudinally extending outwardly projectingmarginal portions, a longitudinally extending relatively abruptly curvedconvex central portion which, at any cross section of the ingot, isdefined by an are having its center substantially on the neutral line(if shrinkage generally normal to said primary side portion, tworelatively smoothly curved concave portions respectively connected tosaid marginal portions and extending toward said central portion, andtwo relatively abruptly curved concave portions re- I spectivelyinterposed between and connecting the opposite longitudinal edges ofsaid central portion with said relatively smoothly curved concaveportions, said relatively smoothly curved concave portions, at any crosssection of the ingot, being defined by arcs having substantially acommon center lying substantially on said neutral line of shrinkage, andsaid relatively abruptly curved concave portions at any cross section ofthe ingot, being defined by arcs having their respective centers onopposite sides of said neutral line of shrinkage, the radii of the arcsdefin ing said relatively smoothly curved concave portimes longer thanthe radii of the arcs defining said convex central portion and saidrelatively abruptly curved concave portions at said cross section.

3. An ingot mold having two oppositely disposed primary side wallportions each of which comprises longitudinally extending outwardlyprojecting marginal wall portions, alongitudinally extending relativelyabruptly curved concave wall portion which, at any cross section of themold, is defined by an are having its center substantially on the moldtransverse center line normal to said primary side wall portion, tworelatively smoothly curved convexwa'll portions respectively connectedto said marginal wall portions and extending toward said central wallsubstantially on said transverse center line, and said relativelyabruptly curved convex wall portions at any cross sectionbeing definedby arcs having their respective centers on opposite sides of saidtransverse center line.

4. An ingot mold having two oppositely disposed primary side wallportions each of which comprises longitudinally extending outwardlyprojecting marginal wall portions, a longitudinally extending relativelyabruptly curved concave wall portion which. at any cross section of the,mold, is defined by an are having its center substantially on the moldtransverse center, line normal-to said primary side wall portion, two

relatively smoothly curved convex wall portions relatively abruptlycurved convex wall portions,

at any cross section being defined by arcs having their respectivecenters on opposite sides of said transverse center line,- the radii ofthe arcs defining said relatively smoothly curved convex wall portionsat any cross section being at least four times longer than the radii ofthe arcs defining said concave central wall portion and said,

relatively abruptly curved convex portions at said-cross section.

5. A metallic ingot of generally rectangular cross section having fourprimary side portions which are arranged in pairs with the primary sideportions of each pair disposed opposite each other, each of said Primaryside portions comprising longitudinally extending outwardly proiectingmarginal portions, a longitudinally extending relatively abruptly curvedconvex central portion which, at any cross section of the ingot,

is defined by an are having its center substantially on the neutral line0! shrinkage generally normal to said primary side portion, tworelatively smoothly curved concave portions respectively connected tosaid marginal portions and extendin toward said central portion, and tworelatively abruptly curved concave portions respectively interposedbetween and connecting the opposite longitudinal edges of said centralportion with said relatively snioothly curved concaveportions, saidrelatively smoothly curved concave portions, at any cross section or theingot, 'being defined by arcs having substantially a common center lyingsubstantially on'said neutral portion, and two relativelyabruptly curvedconvex wall portions respectively interposed between and connecting theopposite longitudinal edges of said central wall portion with saidrelatively line of shrinkage, and said relatively abruptly curvedconcave portions at any cross section of the ingot, being defined byarcs having their respective centers on opposite sides of said neutralline of shrinkage. x

6. A metallic ingot of generally rectangular cross section having fourprimary side portions which are arranged in pairs with the primary sideportions of each pair disposed opposite each other, each of said primaryside portions comprising longitudinally extending outwardly projectingmarginal portions, a longitudinally extending relatively abruptly curvedconvex central portion which, at any cross section or the ingot, isdefined by an are having its center substantially on the neutral line afshrinkage generally normal to said primary side portion, two relativelysmoothly curved concave portions respectively connected to said marginalportions and extending toward said central portion, and two relativelyabruptly curved concave portions respectively interposed between andconnecting the opposite longitudinal edges of said central portion withsaid relatively smoothly curved concave portions, said relativelysmoothly curved concave portions, at any cross section of the ingot,being defined by arcs having substantially a common center lyingsubstantially on said neutral line of shrinkage, and said relativelyabruptly curved concave portions at any cross section of the ingot,being defined by arcs having their respective centers on opposite sidesof said neutral line of shrinkage, the radii of the arcs defining saidrelatively-smoothly curved concave portions at any cross section beingat least four times longer than the radii of the arcs defining saidconvex central portion and said relatively abruptly curved concaveportions at said cross section.

7. An ingot mold of generally rectangular cross section having fourprimary side wall portions which are arranged in pairs with the primaryside wall portions of each pair disposed opposite each other, each ofsaid primary side wall portions comprising longitudinally extendingoutwardly projecting marginal wall portions, a longitudinally extendingrelatively abruptly curved concave wall portion which, at any crosssection of the mold, is defined by an arc having its centersubstantially on the mold transverse center line normal to said primaryside wall portion, two relatively smoothly curved convex wall portionsrespectively connected to said marginal wall portions and extendingtoward said central wall portion, and two relatively abruptly curvedconvex wall portions respectively interposed between and connecting theopposite longitudinal edges of said central wall portion with saidrelatively smoothly curved convex wall portions, said relativelysmoothly curved convex wall portions, at any cross section of the mold,being defined by arcs having substantially a common center lyingsubstantially on said transverse center line, and said relativelyabruptly curved convex wall portions at any cross section being definedby arcs having their respective centers on opposite sides of saidtransverse center line.

8. An ingot mold of generally rectangular cross section having fourprimary side wall portions which are arranged in pairs with the primaryside wall portions of each pair disposed opposite each other, each ofsaid primary side wall portions comprising longitudinally extendingoutwardly projecting marginal wall portions, a longitudinally extendingrelatively abruptly curved concave wall portion which, at any crosssection of the mold, is defined by an are having its centersubstantially on the mold transverse center line normal to said primaryside wall portion, two relatively smoothly curved convex wall portionsrespectively connected to said marginal wall portions and extendingtoward said central wall portion, and two relatively abruptly curvedconvex wall portions respectively interposed between and connecting theopposite longitudinal edges of said central wall portion with saidrelatively smoothly curved convex wall portions, said relativelysmoothly curved convex wall portions, at any cross section of the mold,being defined by arcs having substantially a common center lyingsubstantially on said transverse center line, and said relativelyabruptly curved convex wall portions at any cross section being definedby arcs having their respective centers on opposite sides of saidtransverse center line, the radii of the arcs defining said relativelysmoothly curved convex wall portions at any cross section being at leastfour times longer than the radii of the arcs defining said concavecentral wall portion and said relatively abruptly curved convex portionsat said cross section.

EMIL GATHMANN.

